Entry systems are commonly used to enable a user to remotely access or perform some operation to a vehicle. For example, a vehicle may be equipped with a remote entry system that includes a receiving unit located on the vehicle, which communicates with an electronic key fob. The key fob may enable the user to gain access to the vehicle, start an engine located on the vehicle, and the like. Conventionally, in some applications, a user's engagement of a door handle causes a device within the vehicle to transmit a low-frequency challenge signal to a key fob for authentication. In response, the key fob generates a radio-frequency response signal that is transmitted to the device. The controller then transmits a signal to the door to unlock the doors. Such an authentication process may also apply to starting a vehicle engine.
In some cases, the power of the low frequency signal varies as a result of system and environmental anomalies. The receiving device (e.g., the key fob) may be specifically tuned to the receive low frequency signals having a certain power level. Additionally, the propagation of the low-frequency signal to the receiving device may be detrimentally affected by the signal power level.
The embodiments described herein were conceived in view of these and other disadvantages of conventional entry systems.